1. Field of the Invention
The invention relates generally to stacked-type, multi-flow heat exchangers. More specifically, the invention relates to stacked-type, multi-flow heat exchangers for use in an air conditioning system of a vehicle.
2. Description of Related Art
Referring to FIG. 1, a known stacked-type, multi-flow heat exchanger 70 may comprise a first header pipe 71 and a second header pipe 72 formed opposite first header pipe 71. Heat exchanger 70 also may comprise a plurality of heat transfer tubes 73 extending between first header pipe 71 and second header pipe 72, such that first header pipe 71 and second header pipe 72 are in fluid communication via heat transfer tubes 73. Heat exchanger 70 further may comprise a plurality of corrugated fins 74, which are alternately stacked with heat transfer tubes 73.
Referring to FIG. 2, an enlarged, cross-sectional view of a portion (A) of heat exchanger 70 is depicted. In heat exchanger 70, each end of first header pipe 71 comprises a disk-shaped plug member 75 positioned inside an opening formed in each end of first header pipe 71, and a bracket member 76 fixed to each end of first header pipe 71. Bracket member 76 comprises a cap portion 78 and a rod portion 77. Cap portion 78 is formed over and is fixed to each end of first header pipe 71, and rod portion 77 extends vertically from cap portion 78. Similarly, each end of second header pipe 72 comprises disk-shaped plug member 75 positioned inside an opening formed in each end of second header pipe 72, and bracket member 76 fixed to each end of second header pipe 72. Bracket member 76 comprises cap portion 78 and rod portion 77. Cap portion 78 is formed over and is fixed to each end of second header pipe 72, and rod portion 77 extends vertically from cap portion 78. Moreover, a frame of a vehicle (not shown) may have a plurality of holes formed therethrough, such that each rod portion 77 may be inserted into a corresponding hole. As such, heat exchanger 70 may be fixed to the frame of the vehicle via rod portions 77. Nevertheless, bracket member 76 must be manufactured separately from first header pipe 71 and second header pipe 72, respectively, and subsequently must be fixed to the ends of first header pipe 71 and second header pipe 72, respectively. Consequently, the number of parts of heat exchanger 70 and the manufacturing cost of heat exchanger 70 may increase.
As disclosed in Japanese (Unexamined) Patent Publication No. HEI 11-83377, FIG. 3 depicts another known stacked-type, multi-flow heat exchanger. The heat exchanger comprises a first header pipe 71 and a second header pipe 72, and the ends of first header pipe 71 and second header pipe 72 are compressed or deformed to form a flattened plate portion 79. Flattened plate portion 79 has a substantially rectangular shape and a reduced thickness relative to a thickness of a center portion of first header pipe 71 and second header pipe 72, respectively. Nevertheless, the width or the diameter of flattened plate portion 79 is the same as the width or the diameter of first header pipe 71 and second header pipe 72, respectively. Flattened plate portion 79 also has a hole 80 formed therethrough. In this known heat exchanger, a frame of a vehicle (not shown) may have a plurality of threaded holes formed therethrough, such that a plurality of screws or a plurality of bolts may be used to fix the heat exchanger to the frame of the vehicle via holes 80 and the corresponding threaded holes. Nevertheless, because the ends of first header pipe 71 and second header pipe 72 originally were cylindrical shaped, and subsequently are compressed or deformed to form a substantially rectangular-shaped plate portion, the plate portion may become warped or twisted during the manufacturing process. Consequently, it may be difficult or impossible to fix the heat exchanger to the frame of the vehicle.
Therefore, a need has arisen for heat exchangers that overcome these and other shortcomings of the related art. A technical advantage of the present invention is that a stacked-type, multi-flow heat exchanger may be manufactured having fewer parts than known heat exchangers. Another technical advantage of the present invention is that the heat exchanger may more readily and accurately be fixed to a frame of a vehicle.
According to an embodiment of the present invention, a stacked-type, multi-flow heat exchanger is described. The heat exchanger comprises a first header pipe and a second header pipe formed opposite the first header pipe. The heat exchanger also comprises a plurality of beat transfer tubes extending between the first header pipe and the second header pipe, such that the first header pipe and the second header pipe are in fluid communication via the heat transfer tubes. The heat exchanger further comprises a plurality of fins alternately stacked with the plurality of heat transfer tubes. Moreover at least one of the ends, e.g., each of the ends, of the first header pipe comprises a first tapered portion having a reduced diameter relative to a diameter of a center portion of the first header pipe. In another embodiment, each of the ends of the second header pipe comprises a second tapered portion having a reduced diameter relative to a diameter of a center portion of the second header pipe.
According to yet another embodiment of the present invention, a method of manufacturing a stacked-type, multi-flow heat exchanger is described. The method comprises the step of compressing at least one end, e.g., each of the ends, of a first header pipe of a stacked-type, multi-flow heat exchanger to form a first tapered portion having a reduced diameter relative to a diameter of a center portion of the first header pipe. In still another embodiment, the method also comprises the step of compressing each of the ends of a second header pipe of the heat exchanger to form a second tapered portion having a reduced diameter relative to a diameter of a center portion of the second header pipe.
Other objects, features, and advantages will be apparent to persons of ordinary skill in the art in view of the following detailed description of the invention and the accompanying drawings.